Room temperature angle dispersive powder x-ray diffraction experiments on zircon-type NdVO4 were performed for the first time under quasi-hydrostatic conditions up to 24.5 GPa. The sample undergoes two phase transitions at 6.4 and 19.9 GPa. Our results show that the first transition is a zircon-to-scheelite-type phase transition, which has not been reported before, and contradicts previous non-hydrostatic experiments. In the second transition, NdVO4 transforms into a fergusonite-type structure, which is a monoclinic distortion of scheelite-type. The compressibility and axial anisotropy of the different polymorphs of NdVO4 are reported. A direct comparison of our results with former experimental and theoretical studies on other rare-earth orthovanadates found in literature highlights the importance of the role played by non-hydrostatic stresses in their high-pressure structural behavior.

High-pressure phase transformations in NdVO4 under hydrostatic, conditions: a structural powder x-ray diffraction study

Bettinelli, M
2019-01-01

Abstract

Room temperature angle dispersive powder x-ray diffraction experiments on zircon-type NdVO4 were performed for the first time under quasi-hydrostatic conditions up to 24.5 GPa. The sample undergoes two phase transitions at 6.4 and 19.9 GPa. Our results show that the first transition is a zircon-to-scheelite-type phase transition, which has not been reported before, and contradicts previous non-hydrostatic experiments. In the second transition, NdVO4 transforms into a fergusonite-type structure, which is a monoclinic distortion of scheelite-type. The compressibility and axial anisotropy of the different polymorphs of NdVO4 are reported. A direct comparison of our results with former experimental and theoretical studies on other rare-earth orthovanadates found in literature highlights the importance of the role played by non-hydrostatic stresses in their high-pressure structural behavior.
zircon; scheelite; x-ray diffraction; high pressure; equation of state; phase transition; orthovanadate
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11562/999593
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